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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

Melting Dental Gold



 
 
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  #1  
Old April 20th 08, 07:37 PM posted to rec.crafts.metalworking
external usenet poster
 
Posts: 47
Default Melting Dental Gold

To make a long story short, a customer wants a very special knife,
which is mostly built. But he wants embellishments on the knife that
I've never attempted before, so I'm seeking advice from the good and
knowledgeable people in this group.

He wants a solid gold thumb stud, and he sent me the gold. It is, for
the unsqueamish, a dental bridge and a couple of gold crowns,
apparently harvested from his own mouth a few years ago when he plowed
into a bridge abutment and ate the steering wheel. The doctors had to
reconstruct his face, but they saved his gold teeth, which he sent to
me for this project.

Yeah. He sent me his teeth. You can stop gaping now. Metal content
ensues:

I've looked online and found that dental gold can contain lots of other
metals, including platinum, palladium, silver and even chromium, copper
and zinc. No way to tell what's in this guy's teeth. The fittings don't
look like gold. They look like untarnished copper. They don't have the
look of a 24 karat grille, but they are 40 years old.

I've melted and cast small gold parts before, but only from gold that
was 100% identifiable in terms of alloy. This is a different situation.
I have no way to know what's in this amalgam. I'm afraid to put a torch
to it.

My tooling includes a heat-treating oven that can reach 2200 F, a
propane torch and an AO rig. I have crucibles for precious metal
melting.

How can I make this guy's thumb stud?

-Frank

--
Here's some of my work:
http://www.franksknives.com
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  #2  
Old April 20th 08, 08:12 PM posted to rec.crafts.metalworking
external usenet poster
 
Posts: 149
Default Melting Dental Gold

The only way to be 100% sure of the chemical composition would be to
have it professionally assayed. Separately, you have to remove the
extraneous or undesired elements. To be totally honest, I'd be
tempted to tell the buyer to buy the proper alloy in new material. I
think it is too hard to make a high-quality product from the jewelery
equivalent of "mystery metal".
  #3  
Old April 20th 08, 08:48 PM posted to rec.crafts.metalworking
external usenet poster
 
Posts: 680
Default Melting Dental Gold


"woodworker88" The only way to be 100% sure of the chemical composition
would be to
have it professionally assayed. (clip)

^^^^^^^^^^^^^^^^^^^^^
"Splain to him that it is not a jewelry quality alloy, and offer him a
choice--either buy some other gold, or play with this at his risk. What can
you both lose? You could melt this down and make a simple casting, just to
see how it turns out. It's not going to disappear, and will probably be
more attractive (less disgusting) even if it doesn't work out for the knife.


  #4  
Old April 20th 08, 10:07 PM posted to rec.crafts.metalworking
external usenet poster
 
Posts: 7
Default Melting Dental Gold

I'd say take the dental gold to a refiner (minus the bridge fittings) and
trade it in for casting shot of known alloy and karat. The refiner will give
you the value of the gold content, less a fee. That way, you won't waste
your time messing around with an odd alloy that may not work with your
casting process. Make sure to get enough to provide a button and sprue.

Andrew Werby
www.computersculpture.com



"Frank J Warner" wrote in message
news:200420081037568634%warnerf@veriSPAMMERSDIEzon .net...
To make a long story short, a customer wants a very special knife,
which is mostly built. But he wants embellishments on the knife that
I've never attempted before, so I'm seeking advice from the good and
knowledgeable people in this group.

He wants a solid gold thumb stud, and he sent me the gold. It is, for
the unsqueamish, a dental bridge and a couple of gold crowns,
apparently harvested from his own mouth a few years ago when he plowed
into a bridge abutment and ate the steering wheel. The doctors had to
reconstruct his face, but they saved his gold teeth, which he sent to
me for this project.

Yeah. He sent me his teeth. You can stop gaping now. Metal content
ensues:

I've looked online and found that dental gold can contain lots of other
metals, including platinum, palladium, silver and even chromium, copper
and zinc. No way to tell what's in this guy's teeth. The fittings don't
look like gold. They look like untarnished copper. They don't have the
look of a 24 karat grille, but they are 40 years old.

I've melted and cast small gold parts before, but only from gold that
was 100% identifiable in terms of alloy. This is a different situation.
I have no way to know what's in this amalgam. I'm afraid to put a torch
to it.

My tooling includes a heat-treating oven that can reach 2200 F, a
propane torch and an AO rig. I have crucibles for precious metal
melting.

How can I make this guy's thumb stud?

-Frank

--
Here's some of my work:
http://www.franksknives.com



  #5  
Old April 20th 08, 10:15 PM posted to rec.crafts.metalworking
external usenet poster
 
Posts: 144
Default Melting Dental Gold


"Frank J Warner" wrote in message
news:200420081037568634%warnerf@veriSPAMMERSDIEzon .net...
How can I make this guy's thumb stud?


Look in your local yellow pages for "dental labs". Knock on a door or two;
smile! Ask to talk to the guy who does the casting. Hopefully, he/she will
give you a bit of a tour and discuss casting temperatures and methods. You
might want to arrive late in the day, since the casting person is usually the
last to leave in the evening. Don't be surprised to discover that person does
jewelry casting "on the side" or as a hobby.

A dental lab is nothing more that a miniature foundry/machine shop. The
dentist gives them a mold of the patient's mouth. From that, a technician
designs the cap or bridge and carves it out of wax. Then the part is cast from
dental alloy using the "lost wax" method. Not all dental alloy is gold-based.

Vaughn




  #6  
Old April 20th 08, 10:29 PM posted to rec.crafts.metalworking
external usenet poster
 
Posts: 1,535
Default Melting Dental Gold

On Sun, 20 Apr 2008 10:37:56 -0700, Frank J Warner wrote:

To make a long story short, a customer wants a very special knife, which
is mostly built. But he wants embellishments on the knife that I've
never attempted before, so I'm seeking advice from the good and
knowledgeable people in this group.

He wants a solid gold thumb stud, and he sent me the gold. It is, for
the unsqueamish, a dental bridge and a couple of gold crowns, apparently
harvested from his own mouth a few years ago when he plowed into a
bridge abutment and ate the steering wheel. The doctors had to
reconstruct his face, but they saved his gold teeth, which he sent to me
for this project.

Yeah. He sent me his teeth. You can stop gaping now. Metal content
ensues:

I've looked online and found that dental gold can contain lots of other
metals, including platinum, palladium, silver and even chromium, copper
and zinc. No way to tell what's in this guy's teeth. The fittings don't
look like gold. They look like untarnished copper. They don't have the
look of a 24 karat grille, but they are 40 years old.

I've melted and cast small gold parts before, but only from gold that
was 100% identifiable in terms of alloy. This is a different situation.
I have no way to know what's in this amalgam. I'm afraid to put a torch
to it.

My tooling includes a heat-treating oven that can reach 2200° F, a
propane torch and an AO rig. I have crucibles for precious metal
melting.

How can I make this guy's thumb stud?

-Frank


Set the crowns into the handle for the thumb stud? It'll look as
impressive as hell, in a very peculiar way.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html
  #7  
Old April 20th 08, 11:39 PM posted to rec.crafts.metalworking
external usenet poster
 
Posts: 15
Default Melting Dental Gold

You probably need to post alt.rec.nazis who have plenty of experience in
that sort of thing.


  #8  
Old April 21st 08, 12:18 AM posted to rec.crafts.metalworking
external usenet poster
 
Posts: 181
Default Melting Dental Gold

On Sun, 20 Apr 2008 20:19:35 GMT, "Harold and Susan Vordos"
wrote:
(No snipage due to non propagation of original. See note to Harold at
bottom)

"Frank J Warner" wrote in message
news:200420081037568634%warnerf@veriSPAMMERSDIEzo n.net...
snip----

I've melted and cast small gold parts before, but only from gold that
was 100% identifiable in terms of alloy. This is a different situation.
I have no way to know what's in this amalgam. I'm afraid to put a torch
to it.


Smart man!

Speaking as a person that refined precious metals for well over 20 years,
there's nothing wrong with using dental gold for ornamentation as long is it
does not require any rolling. It is hard to roll, by design. Otherwise it
wouldn't serve well for the intended purpose.

If you intend to cast a given configuration, go for it, with caution.
Be advised that it is not uncommon for a tooth that has an amalgam filling
to be capped with gold, so when you melt the alloy, you may get an emission
of mercury vapors. That can ruin your day if you breath them.

I recommend you break up the teeth by using a hammer and anvil. If
there's any silver amalgam, do remove it mechanically, otherwise you risk
the fumes of which I spoke, but more importantly, you'll contaminate the
gold alloy and render it pretty much useless because of the other
constituents of the amalgam.

The color of dental gold isn't necessarily pretty, but it will serve well
for ornamentation if well polished.

Should you find any of them in the lot you received, do not mix any of the
white alloys with the yellow gold. Separate them before doing any melting.
Some of them are alloys of the platinum group, but the typical white metal
found in the mouth is a high temperature alloy that contains no precious
metals. If you melt gold with the metal, it will get coated and you'll lose
the amount that sticks. It's typically very hard, and breaks instead of
bending. It is also quite blue/white as compared to platinum alloys,
which tend to be colored more towards yellow----much like nickel.

My tooling includes a heat-treating oven that can reach 2200 F, a
propane torch and an AO rig. I have crucibles for precious metal
melting.


Melting gold alloys with anything but an oxygen assisted torch can be a real
challenge. What I'd suggest is to clean the gold well by mechanical means
(anvil and hammer, as I suggested earlier), then go to a jewelry supply
house and ask for a small melting dish. They're made of a white clay (don't
buy one made of brown clay-----they aren't very good quality). Before you
attempt to use the dish, it should be heated slowly, to drive out residual
moisture. Once it has been heated above 212 degrees and it appears to be
stable, play your torch on the dish uniformly, until it is at a dull red
heat. At that point, sprinkle borax over the entire inside surface of the
dish, and melt it. Do this until the dish has a light coating of borax
glass----but not enough to puddle. That way when you melt the gold, it
won't stick to the dish---and will pour easily from the spout. Make sure
the spout is covered even beyond the inside of the dish. Melting with your
furnace will work, but it's much slower, and isn't a requirement.

Any questions? Feel free to contact me on the side.

Harold


Sorry to not add anything, but I know very little about this subject.

Harold, TDS is no longer propagating out to the rest of usenet. I
reported this in tdsnet.general on the 12th and have received no reply.
(Also switched my posting to Easynews / Forte APN.) Saw a post by you
and remembered to look at it more closely *before* I downloaded the
body. It never made it to either NSP I have configured.

Might want to check for your recent posts on Google groups. I think TDS
was broke for over a week before I noticed.
--
William
  #9  
Old April 21st 08, 01:44 AM posted to rec.crafts.metalworking
external usenet poster
 
Posts: 47
Default Melting Dental Gold

In article , Frank J
Warner wrote:

To make a long story short, a customer wants a very special knife,
which is mostly built. But he wants embellishments on the knife that
I've never attempted before, so I'm seeking advice from the good and
knowledgeable people in this group.

He wants a solid gold thumb stud, and he sent me the gold. It is, for
the unsqueamish, a dental bridge and a couple of gold crowns,
apparently harvested from his own mouth a few years ago when he plowed
into a bridge abutment and ate the steering wheel. The doctors had to
reconstruct his face, but they saved his gold teeth, which he sent to
me for this project.

Yeah. He sent me his teeth. You can stop gaping now. Metal content
ensues:

I've looked online and found that dental gold can contain lots of other
metals, including platinum, palladium, silver and even chromium, copper
and zinc. No way to tell what's in this guy's teeth. The fittings don't
look like gold. They look like untarnished copper. They don't have the
look of a 24 karat grille, but they are 40 years old.

I've melted and cast small gold parts before, but only from gold that
was 100% identifiable in terms of alloy. This is a different situation.
I have no way to know what's in this amalgam. I'm afraid to put a torch
to it.

My tooling includes a heat-treating oven that can reach 2200 F, a
propane torch and an AO rig. I have crucibles for precious metal
melting.

How can I make this guy's thumb stud?

-Frank


Replying to my own post, I melted one of the small crowns not attached
to the main bridge piece with a propane torch this afternoon. It melted
just like one of those old dimes I used to melt with my daddy's propane
torch back in the 60s; the real silver lady liberty dimes.

The resulting lump was more silver than gold in color, so I suspect
this amalgam is heavy with silver.

The bottom line is that it melted in a familiar way, so I'm probably
able to melt and cast the remainder into a piece I can machine for a
thumb stud.

The color will be slightly off. This knife uses pre-ban elephant ivory
for the scales, and I'm using gold-plated screws to hold it all
together. The thumb stud will be halfway between the color of the blade
and the color of the screws.

-Frank

--
Here's some of my work:
http://www.franksknives.com
  #10  
Old April 21st 08, 02:07 AM posted to rec.crafts.metalworking
external usenet poster
 
Posts: 93
Default Melting Dental Gold


"Frank J Warner" wrote in message
news:200420081644277464%warnerf@veriSPAMMERSDIEzon .net...
In article , Frank J
Warner wrote:

To make a long story short, a customer wants a very special knife,
which is mostly built. But he wants embellishments on the knife that
I've never attempted before, so I'm seeking advice from the good and
knowledgeable people in this group.

He wants a solid gold thumb stud, and he sent me the gold. It is, for
the unsqueamish, a dental bridge and a couple of gold crowns,
apparently harvested from his own mouth a few years ago when he plowed
into a bridge abutment and ate the steering wheel. The doctors had to
reconstruct his face, but they saved his gold teeth, which he sent to
me for this project.

Yeah. He sent me his teeth. You can stop gaping now. Metal content
ensues:

I've looked online and found that dental gold can contain lots of other
metals, including platinum, palladium, silver and even chromium, copper
and zinc. No way to tell what's in this guy's teeth. The fittings don't
look like gold. They look like untarnished copper. They don't have the
look of a 24 karat grille, but they are 40 years old.

I've melted and cast small gold parts before, but only from gold that
was 100% identifiable in terms of alloy. This is a different situation.
I have no way to know what's in this amalgam. I'm afraid to put a torch
to it.

My tooling includes a heat-treating oven that can reach 2200 F, a
propane torch and an AO rig. I have crucibles for precious metal
melting.

How can I make this guy's thumb stud?

-Frank


Replying to my own post, I melted one of the small crowns not attached
to the main bridge piece with a propane torch this afternoon. It melted
just like one of those old dimes I used to melt with my daddy's propane
torch back in the 60s; the real silver lady liberty dimes.

The resulting lump was more silver than gold in color, so I suspect
this amalgam is heavy with silver.

The bottom line is that it melted in a familiar way, so I'm probably
able to melt and cast the remainder into a piece I can machine for a
thumb stud.

The color will be slightly off. This knife uses pre-ban elephant ivory
for the scales, and I'm using gold-plated screws to hold it all
together. The thumb stud will be halfway between the color of the blade
and the color of the screws.

-Frank

--
Here's some of my work:
http://www.franksknives.com




What about giving your dentist a call and see if he or she can tell you the
composition basics and point you to a lab to get the finite details?
Dentists may be worth something besides pain now!

All the best,

Rob


 




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